Fig. 5: CA1 PV cells undergo electrophysiological maturation of passive and action potential firing properties.

A PV cells were visualized using either Pvalb-TdTomato or Tac1-Cre x floxed eGFP (see Supplemental Figs. S5 and S6). Mouse clipart from BioRender (permissions provided). B Representative, amplitude-normalized repolarization traces to highlight differences in membrane time constant following a −50 pA current injection at different developmental timepoints. C Membrane time constant is significantly prolonged in neonatal mice (F = 40.68, one-way ANOVA; p < 0.0001 for post-hoc multiple comparisons with every other developmental timepoint). D Action potential half-width is significantly prolonged in neonatal mice (F = 28, one-way ANOVA; p < 0.0001 for post-hoc multiple comparisons with every other developmental timepoint). E Representative, amplitude-normalized single action potential traces to highlight differences in half-width at different developmental timepoints. F Representative action potential trains elicited by various current injections depicted below each train to illustrate change in maximum action potential firing frequency during development. Traces shown are those just below threshold for depolarization-induced block of action potential firing. G Maximum action potential firing frequency is significantly decreased in neonatal mice (F = 28.3, one-way ANOVA; p < 0.001 for post-hoc multiple comparison test with juvenile mice, and p < 0.0001 for post-hoc multiple comparison test with preadolescent and adult mice). Juvenile mice also show a significantly decreased maximum action potential firing frequency compared to preadolescent mice (one-way ANOVA post-hoc multiple comparison test; p = 0.0039). H Current required for depolarization-induced block of action potential firing is significantly decreased in neonatal mice (F = 8.36, one-way ANOVA; p < 0.01 for post-hoc multiple comparison test with juvenile and adult mice, and p < 0.0001 for post-hoc multiple comparison test with preadolescent mice). Symbols are mean ± SEM. AP = action potential; depolarization block = Current required for depolarization-induced block of action potential firing. **p < 0.01; ***p < 0.001; ****p < 0.0001; # = juvenile mice significantly different than adult mice in one-way ANOVA post-hoc multiple comparison test.